A review of the literature reveals how little we know of the factors controlling, altering of modifying brain development. During pregnancy, women are more than often subjected to different environmental stressors and/or drugs, unaware of the consequences that this may have on the fetus. Previous studies have concentrated mainly on the short term effects, omitting analysis of long term effects which are equally important. In this study the laboratory rat will be used as a model to investigate how perinatal exposure to agents such as stress, postnatal handling, ACTH, glucocorticoids and nicotine might induce alterations in the reproductive physiology and/or brain neurochemistry of the offspring that persist into adulthood. This project will provide students with the opportunity to study and anatomy and neurochemistry of several brain areas. Among the brain areas to be studied are the VMN and the POA, which are involved in the regulation of reproductive processes and the hippocampus, a brain area involved in learning, memory and essential in the feedback regulation of the stress response. In addition, they will explore the enkephalinergic system, and the serotonin and benzodiazepine receptor systems, which are implicated in the process of sexual differentiation of the brain, in the pathology of depressive illness, and in the stress response. The long-term goal of this proposal is to establish a research program in developmental neuroendocrinology, which is currently nonexistent in Puerto Rico.